JP4912445B2 - Stretchable composite sheet and manufacturing method - Google Patents

Description

  The present invention relates to an improved method for producing an extensible multilayer composite sheet, wherein at least one layer in the multilayer composite sheet comprises multicomponent spiral crimped fibers.

  Nonwoven webs made from multicomponent filaments are known in the art. This product is usually heavy, has a high loft, and the fibers are highly bonded at their intersections. For example, U.S. Patent No. 5,637,049 to Davies et al. Contains two crimped fibers that are bonded and bonded mechanically by the connection of spirals in the crimped fibers and by melting of the low melt adhesive polymer component. The component fiber material is described. In order to bond the fibers of adjacent webs together, a single treatment step can develop crimps and activate potential adhesive components, or develop crimps, followed by Thus, the adhesive component can be activated. During the process of preventing fiber crimp, crimp is developed under conditions where no significant pressure is applied.

  U.S. Patent No. 6,057,049 to Okawahara et al. Produced by conjugate spinning of polyethylene terephthalate copolymerized with structural units having metal sulfonate groups and parallel filaments of polyethylene terephthalate or poly (1,4-butylene terephthalate). The finish of a nonwoven fabric comprising a modified two-component polyester filament is described. Prior to forming the nonwoven, the filaments are mechanically crimped. By exposing to infrared radiation while the filament is in a relaxed state, the fabric becomes stretchable. During the infrared heating process, the conjugate filament develops a three-dimensional crimp and a high loft.

  U.S. Patent No. 6,057,049 to Pike et al. Describes a process of melt spinning a continuous multicomponent polymer filament, a step of drawing the filament, and a multicomponent filament so that the filament has an invisible helical (spiral) crimp. A method for producing a nonwoven fabric is described that includes a step of at least partially quenching, a step of activating subclinical helical crimps, and then forming crimped continuous multicomponent filaments in the nonwoven fabric. The resulting nonwoven is described as being substantially stable and uniform and may have a high loft.

  Also, US Pat. No. 6,057,049 describes an extensible nonwoven web comprising a plurality of bicomponent fibers that can also be blended with non-bicomponent fibers that are point bonded prior to heating to develop crimp in the filament. Is described. Bicomponent filaments comprise a polyester component and another polymer component, preferably a polyolefin or polyamide. The heating step causes the bonded webs to shrink and when stretched to 30%, a nonwoven is obtained that exhibits elastic recovery in both the machine direction and the transverse direction.

Multilayer composite elastic nonwoven materials are also known in the art. Examples of multilayer elastic nonwoven materials include “stretch-bonded” and “neck-bonded” laminates. Stretch bond laminates are produced by bonding the collectable layer to the elastic layer while the elastic layer is in stretch condition so that the collectable layer assembles upon relaxation of the layer. A “neckbond laminate” is produced by bonding a necked inelastic layer with an elastic layer when the inelastic layer is in stretch conditions. The elastic layer generally comprises an elastic film or an elastic nonwoven web. The manufacture of these composite nonwoven materials requires one layer to be in stretch conditions before being bonded to the second layer. When an elastic film is used as the elastic layer, elastic composites are generally unsuitable for some apparel end uses due to the high retractive force of the elastic film.

  U.S. Pat. No. 6,057,097 to Evans et al. Describes a self-crimped composite filament comprising a lateral eccentric assembly of at least two synthetic polyesters, the first of the two polyesters being partially crystalline. Here, the chemical repeat unit of the crystalline region is in an unstretched stable structure, and the second of the two polyesters is partially crystalline, where the chemical repeat unit of the crystalline region is The structure approximates the length of the structure of a fully extended chemical repeat unit. Composite filaments exhibit a high degree of helical crimping against the restraints imposed by a high drive-in number of woven structures that retain their crimping potential significantly better despite the application of extended pressure and high temperature Can be made. In the crimping potential, composite filaments increase rather than decrease when annealed under tension as part of the fiber manufacturing process. This filament is described as being useful in knitted, woven and non-woven fabrics.

  Stretchable nonwoven fabrics comprising spiral crimped multicomponent fibers known in the art are generally due to the presence of spiral crimp fibers on the nonwoven surface that contribute to surface roughness and pilling, etc. The touch is poor. This is true even when the spiral crimped fibers are blended with other textile fibers such as cotton, rayon, sub-denier polyester or microfibers such as nylon, polyethylene, polypropylene and the like. By blending with spiral crimped fibers, the desirable properties of these other textile fibers, such as soft hand, absorbency, repellency, dye uniformity, etc. are diminished. Non-woven fabrics known in the art containing spiral crimped fibers blended with other fibers generally have a relatively rough surface caused by fully activated spiral crimped fibers, and other blends described above. Due to the surface characteristics that have been made, it has limited uses such as furniture fabrics, clothing and the like.

  Tough, durable, and uniform, and low in surface properties, strength, uniformity, and multilayer nonwovens with improved combinations of drapes for end uses such as clothing and furniture There remains a need for costly stretchable composite sheets. It is further desirable to reduce the complexity of the manufacturing process by providing an elastic composite sheet manufacturing process that does not require one layer to be stretched during the manufacturing process.

US Pat. No. 3,595,731 US Pat. No. 5,102,724 US Pat. No. 5,382,400 International Publication No. 00/66821 Pamphlet U.S. Pat. No. 3,671,379

The present invention provides that the multicomponent fibers have a cross section and a length and are arranged in substantially different lateral eccentric regions across the cross section of the multicomponent filament, and substantially along the length of the multicomponent filament. A first polymer layer comprising at least 20% by weight of spirally crimped multicomponent fibers comprising a first polymer component and a second polymer component that are continuously stretched;
A second polymer layer comprising less than 20 wt% laterally eccentric spiral crimped multicomponent fibers and intermittently bonded to the first layer;
A stretchable multilayer composite sheet comprising:
The spiral crimped multicomponent fibers in the first layer form a spiral crimped fiber segment located substantially in the plane of the first layer and connect the bonds; and Two layers comprise a multilayer composite sheet that forms a buckled out-of-plane segment between the bonds.

The present invention also provides
The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament Providing a spirally crimpable polymer layer comprising at least 20% by weight of spirally crimpable multicomponent fibers comprising a first polymer component and a second polymer component;
Providing a non-spiral crimped polymer layer comprising less than about 20% by weight of side eccentric spiral crimped multicomponent fibers;
Intermittently bonding the first polymer layer to the second polymer layer by a plurality of bonds to form a bonded multilayer composite sheet;
Heating the bonded multi-layer composite sheet to a temperature sufficient to develop a three-dimensional spiral crimp in the spiral crimpable fibers in the first layer, wherein the area is at least an area based on the original sheet area; Shrinking the bonded multilayer composite sheet by 10% and buckling the second polymer layer between the bonds;
A method for producing a stretchable multilayer composite sheet comprising:

  Nonwoven fabrics made according to the method of the present invention have an improved combination of elastic strength, aesthetics, fabric feel, drape and strength compared to bonded multicomponent nonwoven fabrics known in the art.

Less than 20% by weight of the first polymer layer comprising at least 20% by weight, preferably at least 50% by weight, and most preferably at least 70% by weight of the side eccentric spiral crimped multicomponent fiber Is produced by intermittently bonding to a second polymer layer comprising less than 10% by weight and most preferably 0% by weight of spirally crimped fibers. Is done. The first fibrous polymer layer can consist essentially of 100% by weight of spirally crimped fibers. Subsequent to bonding, heating activates spiral crimping of the fibers in the first fiber layer. It is important to bond the layers together with discontinuous patterns such as point bonds, lines, etc., separated by a distance sufficient to crimp the spiral crimpable fiber substantially equally and uniformly between the bonds. is there. During the heating step, the second layer does not shrink to a substantial degree so that the fibers in the first fiber layer develop a spiral crimp, but the first layer shrinks in the plane of the composite sheet. The shrinkage of the first layer causes the second layer to buckle between bonds, forming an aggregate layer attached to the first fiber layer. In a preferred embodiment, the first layer and the second layer are nonwoven webs comprising prebonded nonwovens. The bonded, heat treated multilayer nonwoven fabric made in accordance with the present invention is elastic, conformable, tough and draped.

  The term “polyester” as used herein is intended to encompass a polymer in which at least 85% of the repeating units are the condensation product of a dicarboxylic acid and a dihydroxy alcohol having linkages resulting from the formation of ester units. The This includes aromatic, aliphatic, saturated and unsaturated diacids and dialcohols. The term “polyester” as used herein also includes copolymers (eg, block, graft, random and alternating copolymers), blends and modifications thereof. Examples of polyesters include poly (ethylene terephthalate), which is a condensation product of ethylene glycol and terephthalic acid, and poly (trimethylene terephthalate), which is a condensation product of 1,3-propanediol and terephthalic acid. .

As used herein, the terms “nonwoven”, “nonwoven web” and “nonwoven layer” refer to individual fibers that form a flat material without an identifiable pattern, in contrast to a knitted or woven fabric. Mean the structure of filaments or yarns located in a random manner. The term “multilayer nonwoven” is used herein to refer to a nonwoven comprising at least two layers, each layer comprising a nonwoven web. The term “bilayer nonwoven fabric” is used to refer to a multilayer fabric composed of two nonwoven layers.

  The term “multilayer composite sheet” is used herein to refer to a multilayer structure comprising at least two layers of material, wherein at least one of said layers comprises a sheet structure such as a film, fabric or web. Is done. For example, the multilayer composite sheet may comprise at least one layer of knitted fabric, woven fabric or non-woven fabric. Other layers suitable for making multilayer composite sheets include an array of filaments or warps, such as an array of spiral crimpable filaments or warps.

  The term “machine direction” (MD) is used herein to refer to the direction in which the nonwoven web is produced. The term “lateral direction” (XD) refers to a direction generally perpendicular to the longitudinal direction.

  As used herein, the terms “multicomponent filament” and “multicomponent fiber” refer to any filament or composed of at least two different polymers spun together to form a single filament or fiber. Refers to fiber. The term “fiber” as used herein includes continuous filaments and discontinuous (staple) fibers. By the term “different polymers”, each of the at least two polymer components is arranged in different substantially constant regions across the cross-section of the multicomponent fiber and is substantially continuously along the length of the fiber. It means to stretch. The polymer components in the spiral crimpable fiber useful in forming the spiral crimpable layer may be chemically different or they may have the same chemical composition. If they are chemically identical, they must differ in isomeric form, crystallinity, shrinkage, elasticity or other properties in order to provide spirally crimpable fibers. Multicomponent fibers are distinguished from fibers that are extruded from a homogeneous melt blend of polymeric materials that do not form different polymer regions. One or more polymer components in the multicomponent fiber can be a blend of different polymers. The multicomponent fibers useful in the present invention have a lateral eccentric cross section, that is, the polymer components are arranged in an eccentric relationship in the cross section of the fiber. Preferably, the multicomponent fiber is a bicomponent fiber made from two different polymers and having an eccentric sheath-core or parallel array of polymers. Most preferably, the multicomponent fiber is a parallel bicomponent fiber. When the bicomponent fiber has an eccentric sheath-core configuration, the sheath preferably has a low melting polymer to promote hot spot bonding of the nonwoven layer prior to heat treatment. As used herein, the term “single component” fiber refers to a fiber made from a single polymer component. A single polymer component can consist essentially of a single polymer or can be a blend of polymers.

  The term “multicomponent web” as used herein refers to a nonwoven web comprising multicomponent fibers. The term “bicomponent web” as used herein refers to a nonwoven web comprising bicomponent fibers. Multicomponent and bicomponent webs may comprise blends of multicomponent fibers with single component fibers. The nonwoven layer used to form the multilayer composite sheet of the present invention can be made from either short (staple) fibers or continuous filaments.

As used herein, the term “spunbond” fiber refers to extruding a molten thermoplastic polymer material as a fiber from a capillary of a spinneret having a diameter of a plurality of fine, usually circular, extruded filaments, and then drawn. Means a fiber formed by being reduced more quickly. Other fiber cross-sectional shapes such as oval, multilobular, etc. can also be used. Spunbond fibers are generally continuous filaments and have an average diameter of greater than about 5 micrometers. Spunbond nonwovens or webs are formed by randomly placing spunbond fibers on a collection surface or belt, such as a perforated screen, using methods known in the art. Spunbond webs are typically bonded by methods known in the art such as by hotpointing the web at a plurality of discrete thermal bond points, lines, etc. located across the surface of the spunbond fabric. Is done.

  The term “substantially non-woven web” is used herein to describe a non-woven web with little or no interfiber bonding. In some instances, it may be desirable to pre-integrate one or more nonwoven layers prior to assembling the layers to form a multilayer composite sheet. Pre-integration improves web stickiness and handling and keeps the fibers in each individual web separated from adjacent web fibers. Pre-integration of the web can be achieved by using a very light calendering process or by passing the fabric through a lightly patterned roll nip.

  The term “elastic” as used herein when applied to a nonwoven or multilayer composite sheet, the fabric or composite sheet is stretched at least 12% of the initial length, preferably 20%, and then released. Sometimes the nonwoven or composite sheet recovers, and the extension (or permanent set) remaining after the release of the stretching force is less than 5% calculated based on the initial length of the nonwoven or composite sheet before stretching To do. A method for determining this property is provided in more detail below.

  Side eccentric multicomponent fibers comprising two or more synthetic components with different contractility are known in the art. Such fibers can form a three-dimensional spiral crimp if the crimp is activated by subjecting the fiber to a shrinking condition in an essentially tensionless state. The amount of crimp is directly related to the difference in shrinkage between the polymer components in the fiber. When multicomponent fibers are spun in a parallel structure, the crimped fibers formed after crimp activation have a high shrinkage component inside the spiral helix and a low shrinkage component outside the helix. In this specification, such crimps are referred to as “spiral crimps”. Spiral crimped fibers are generally distinguished from mechanically crimped fibers such as stuffer-box crimped fibers having a two-dimensional crimp.

  A variety of thermoplastic polymers can be used to form a multicomponent fiber component capable of developing a three-dimensional spiral crimp. Examples of suitable thermoplastic resin combinations to form spiral crimped multicomponent fibers include crystalline polypropylene / high density polyethylene, crystalline polypropylene / ethylene-vinyl acetate copolymer, polyethylene terephthalate / high density polyethylene, poly (Ethylene terephthalate) / poly (trimethylene terephthalate), poly (ethylene terephthalate) / poly (1,4-butylene terephthalate) and nylon 66 / nylon 6.

In order to achieve a high level of three-dimensional spiral crimp, the polymer component of the multicomponent fiber is preferably selected according to the teachings in Evans, which is incorporated herein by reference. The Evans patent is that the polymer component is a partially crystalline polyester and the first component is in an unstretched stable structure that does not exceed 90% of the length of the fully stretched chemical repeat unit structure Having a chemical repeat unit in the crystalline region, wherein the second component is in a structure closer to the length of the fully extended chemical repeat unit structure than the first polyester. Bicomponent fibers having repeating units are described. The term "partial crystallinity" used when defining Evans filaments serves to remove from the scope of the present invention the limited state of full crystallinity that eliminates the possibility of shrinkage. The amount of crystallinity defined by the term “partial crystallinity” is the minimum level (ie, initially detectable by X-ray diffraction means) and the complete crystallinity only in the presence of some crystallinity Any of the amount has the maximum level that is missing. Examples of suitable fully stretched polyesters are poly (ethylene terephthalate), poly (cyclohexyl 1,4-dimethylene terephthalate), copolymers thereof, and copolymers of ethylene terephthalate and sodium salt of ethylene sulfoisophthalate. . Examples of suitable unstretched polyesters are poly (trimethylene terephthalate), poly (tetramethylene terephthalate), poly (trimethylene dinaphthalate), poly (trimethylene dibenzoate), those with ethylene sodium sulfoisophthalate Copolymers, and selected polyester ethers. When ethylene sodium sulfoisophthalate copolymer is used, it is preferably a minor component, i.e. present in an amount of less than 5 mol%, preferably in an amount of about 2 mol%. In a particularly preferred embodiment, the two polyesters are poly (ethylene terephthalate) and poly (trimethylene terephthalate). Other polymer combinations generally must be heated in tension to develop spiral crimps, whereas Evans bicomponent filaments are highly advanced when heated under tension. Helical crimps can be expressed. Evans bicomponent filaments have a high degree of spiral crimp and generally act as a spring and have a recoil action whenever an extension force is applied and released. Other partially crystalline polymers that are suitable for use in the present invention include syndiotactic polypropylene that crystallizes in an elongated structure and isotactic polypropylene that crystallizes in an unstretched helical structure. .

  In the multilayer composite sheet of the present invention, the first fiber layer is referred to herein as a spiral crimped layer, and the second layer is referred to herein as a non-spiral crimped layer. As long as the spiral crimped layer can include non-spiral crimped fibers and the level meets the above specified requirements, the non-spiral crimped layer is a low level spiral. It should also be understood that crimped fibers can be included. Also, the non-spiral crimpable layer must be a layer that does not shrink to a significant degree during heat treatment, as compared to the spiral crimpable layer, so that it forms an aggregate layer in the final composite sheet. . When heat treated under the conditions used to heat treat the combined multilayer components, the non-spiral crimpable layer is preferably up to about 20% in area, more preferably less than 10% in area. Shrink until. Preferably, the surface area shrinkage of the spiral crimpable layer is at least 20% greater than the area shrinkage of the non-spiral crimpable layer. More preferably, the surface area shrinkage of the spiral crimpable layer is at least 40% greater than the surface area shrinkage of the non-spiral crimpable layer.

  One or more layers of the multilayer composite sheet of the present invention may be a nonwoven layer. A nonwoven layer suitable for use in the composite sheet of the present invention can be made from staple fibers using methods known in the art such as carding, garnetting or air laying. The staple fibers preferably have a denier per filament between about 0.5 and 6.0, and a fiber length between about 0.5 inches (1.27 cm) and 4 inches (10.1 cm). Have For processing with carding equipment, preferably the multicomponent staple fibers have an initial helical crimp level characterized by a crimp index (CI) of about 45% or less, preferably in the range of about 8% to 15%. Have. Methods for determining these crimp values are provided below before the examples. Multicomponent fibers used to produce a nonwoven layer suitable for use as a spiral crimp layer preferably have comparable initial spiral crimp levels. Alternatively, the multicomponent fiber can be crimped mechanically. However, when providing a fiber having zero initial crimp and then spinning the multicomponent fiber under conditions that are mechanically crimped to form a card web, the resulting nonwoven fabric is generally It has been found to have a lower level of elongation than that produced from fibers having a range of initial spiral crimps. The polymer component in the multicomponent fiber is preferably selected so that there is no significant separation of the polymer component during the web forming process. While airlaid webs are substantially random or isotropic, staple webs produced by carding are generally oriented primarily in the machine direction.

Suitable staple fibers for blending with the spiral crimpable multicomponent fibers used to form the spiral crimpable nonwoven layer include natural fibers such as cotton, wool and silk, and polyamides, Examples include synthetic fibers including polyester, polyacrylonitrile, polyethylene, polypropylene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, and polyurethane fibers. Staple fibers useful for forming a non-spiral crimpable nonwoven layer include polyester, polyamide, polyolefin and cellulose fibers. When a staple fiber web is used as the non-spiral crimped layer, the staple fibers can be blended with low melting thermoplastic binder fibers to promote composite sheet bonding.

  One or more of the layers in the multilayer composite sheet of the present invention may comprise continuous filaments. For example, continuous filament webs can be produced using methods known in the art such as spunbond. For example, continuous filament spunbonding can be achieved by feeding two or more polymer components as a melt stream from separate extruders to a spinneret comprising one or more rows of multicomponent extrusion orifices. A spiral crimpable layer comprising a woven web can be produced. The spinneret orifice and spin pack designs are selected to provide filaments with the desired cross-section and denier per filament. A continuous filament multicomponent nonwoven web suitable for use as the spiral crimped layer of the present invention preferably comprises at least 40% by weight, more preferably at least 60% by weight of spirally crimped multicomponent filaments. Comprising. The filaments in the spiral crimp layer can consist of 100% multicomponent filaments. Preferably, the spunbond filament has a denier per filament between about 0.5 and 10.0. Multicomponent continuous filaments preferably have an initial helical crimp level characterized by a crimp index (CI) of about 60% or less. Spiral crimped fibers (whether staples or continuous) are characterized by a crimped expression (CD) value in which the amount (% CD-% CI) is 15% or more, more preferably 25% or more. To do. When the spiral crimped multicomponent filament is a bicomponent filament, the ratio of the two polymer components in each filament is preferably between about 10:90 and 90:10 based on volume (eg, meter pump More preferably between about 30:70 and 70:30, and most preferably between about 40:60 and 60:40.

  Separate spin packs can be used to provide the web with a mixture of different multicomponent filaments. Here, the different filaments are spun from different spin packs. Alternatively, single component fibers can be spun from one or more spin packs to form a spunbond nonwoven web comprising single component and multicomponent filaments.

In the spunbond process, the filament is extruded from a spinneret as a filament moving curtain down and passed through a quench zone. Here, for example, the filaments are cooled by cross-flow air quenching supplied by a blower on one or both sides of the filament curtain. To avoid “shadowing” where one row of filaments effectively blocks adjacent rows of filaments from the quenching air in the quench zone, the spinneret alternating rows of extrusion orifices may be staggered with respect to each other. it can. The length of the quench zone is selected so that the filaments are cooled to a temperature at which the filaments do not stick together when leaving the quench zone. It is generally not necessary for the filament to solidify completely at the exit of the quench zone. Quenched filaments typically pass through a fiber drawing device or aspirator located below the spinneret. Such fiber pulling devices or aspirators are well known in the art and generally include an elongated vertical passage where the filaments are pulled by drawing air entering from the passage side and flowing downward through the passage. Aspirating air causes pulling of the filament proximal to the spinneret plate surface, helps to carry the quenched filament, and deposits it on the perforated surface located below the fiber pulling device Drawing tension is provided. Alternatively, the fibers can be mechanically extracted using a driven draw roll inserted between the quench zone and the suction jet. When using a pulling roll to provide pulling tension that causes pulling of the filament proximal to the spinneret surface, the suction jet is collected with the pulling roll to serve as a forwarding jet that deposits the filament below the web forming surface. Can be placed between the surface. A vacuum can be placed under the forming surface to remove the suction air and draw the filaments against the forming surface.

  The spiral crimpable fiber layer is preferably a substantially unbonded nonwoven web of spiral crimpable multicomponent fibers. In a particularly preferred embodiment, the spiral crimped fiber layer is a bicomponent nonwoven web. Preferably, during the heating step, the fibers are sufficient during the heat treatment step to shrink the combined composite sheet by at least 10% by area, preferably by at least 20% by area, based on the initial sheet area. Any pre-integration of the spiral crimped nonwoven layer is sufficiently low so that a proper crimp can be developed. The percent area shrinkage of the heat-treated pre-integrated spiral crimpable nonwoven layer is at least 90% of the same non-pre-integrated identical spiral-crimp nonwoven layer that undergoes the same heat treatment step. , Preferably 95%, the pre-integrated spiral crimped nonwoven layer is considered substantially unbonded. In a preferred embodiment, the bonded multilayer composite sheet shrinks in the machine direction and / or transverse direction by at least about 20%, more preferably at least 40%, during the heat treatment (crimp activation) step. Examples of suitable multicomponent nonwoven webs include spiral crimped multicomponent card webs, cross-laid (cross-wrapped) webs and continuous filament spunbond webs.

  Whether the spirally crimped filaments or yarns stretched longitudinally or transversely across the composite sheet are tensioned or relaxed (ie not tensioned) Alternatively, a semi-relaxed parallel warp can be used as the spiral crimped layer. Such an array of filaments or yarns should be capable of shrinking the combined composite sheet by at least 10% in area relative to the original sheet area before shrinkage.

  The spiral crimpable layer is selected so that the desired stretch properties are obtained in the final composite sheet. For example, if stretch properties are desired in the machine direction with minimal stretch in the transverse direction, warp yarns of parallel spiral crimped filaments aligned in the machine direction of a composite sheet or directional (MD oriented) card web Can be used. Where bi-directional stretch properties are desired, i.e. more random of spirally crimped continuous filaments or yarns such as airlaid webs and substantially unbonded spunbond webs in both the machine and transverse directions Different layers can be used.

A non-spiral crimpable layer is a combination of multilayer composites between heat treatment steps so that the spiral crimpable fiber layer contracts when the fibers in the spiral crimpable fiber layer develop spiral crimps. It must be a gatherable layer that can be gathered and buckled between. The non-spiral crimpable layer preferably does not shrink to any substantial degree during the heat treatment process so as to collect between bonds. Examples of suitable materials for use as the non-spiral crimped layer include nonwoven webs and fiber fabrics and films such as knitted or woven fabrics. In a preferred embodiment, the non-spiral crimpable layer is a nonwoven web. The non-spiral crimpable layer preferably has a thickness between about 0.3 mm and 1.0 mm before shrinking and buckling. The overall thickness of the composite sheet is preferably less than about 4 mm. Also, the composite sheet preferably has a volume of less than about 30 cm ³ / g. Composite sheets in which the non-spiral crimpable layer is a film are useful in end uses such as raincoats, wind jackets, medical devices and the like. The film used in the composite sheet of the present invention may or may not be breathable. Examples of breathable films suitable for use in the present invention include E.I. of Wilmington, Delaware. I. Copolyetherester films such as Hytrel (R), available from EI du Pont de Nemours and Company, Wilmington, DE (DuPont). A composite sheet in which the non-spiral crimped layer is a knitted fabric, a woven fabric or a non-woven fabric, or a web is suitable for end uses of clothing and furniture including upholstery, clothing and the like.

  Nonwoven webs suitable for use as the non-spiral crimped layer include bonded webs and unbonded webs. An unbonded web between about 0.2 mm and 10 mm thick is suitable. Unbonded webs with high volumes generally reduce the layer thickness to promote thermal patterns that are bonded to other layers in the multilayer composite sheet, as well as to assemble during the heat treatment process. Requires some pre-integration to reduce. Prior to bonding to the spiral crimpable fiber layer, a non-spiral crimpable nonwoven layer can be previously bonded over part or all of its surface. In some cases, the fibers of the layer remain separated from the spiral crimpable fibers of the spiral crimpable layer, and thus separate the non-spiral crimpable layer when the spiral crimpable layer shrinks. It may be desirable to pre-bond the non-spiral crimped nonwoven layer in order to assemble together and achieve better surface stability. Pre-bonding the non-spiral crimped nonwoven layer using methods known in the art such as hydraulic or mechanical needling, hot or ultrasonic point bonding, or thermal area bonding. Can do.

  In separate process steps, the individual layers in the multilayer composite sheet of the present invention can be manufactured, combined, bonded and heat treated. Alternatively, the layers can be combined, combined, and heat treated in a continuous process, in a series fashion. If nonwoven layers are used, the individual layers forming the multilayer nonwoven composite can be integrated by calendering prior to bonding and heat treatment. Except for the bond attached to the non-spiral crimpable layer, any of the spiral-crimp multicomponent nonwoven layers in advance so that the spiral-crimp nonwoven layer remains substantially unbonded. Integration is preferably limited.

  The spiral and non-spiral crimp layers are assembled and bonded together by using a bond prior to heat treatment, such as an intermittent pattern of dots or lines. Prior to the heating step, pattern bonding can be performed in series. Alternatively, the combined composite sheets can be collected, for example by winding on a roll, and then heat treated in the next step. In preferred embodiments, the layers are bonded intermittently using hot spot bonding or ultrasonic point bonding. Hot spot bonding applies heat and pressure at discontinuous points on the surface of the multilayer composite, for example, by passing the layered structure through a nip formed by a heat patterned calender roll and smooth roll. Including that. During thermal bonding, one or more of the polymer components in at least one of the layers is a thermal pattern to form a melt bond that holds the individual layers together to form an adhesively bonded multilayer composite sheet Corresponding to the bumps that occurred on the forming roll, it partially melts in the discontinuous areas. The bond roll pattern can be any of those known in the art and is preferably a discontinuous point or line bond pattern.

In another embodiment, the spiral crimped fiber layer can be bonded to a non-spiral crimped fiber layer, such as a non-spiral crimped nonwoven layer. A liquid binder, such as latex, can be applied by printing in a pattern on a multilayer nonwoven. Where a fibrous web layer is used, the liquid binder is preferably applied to the multilayer composite in a manner that forms a bond that extends through the entire thickness of the web. After assembling or applying the layers to the inner surface of either or both of the crimped or non-crimpable layers, the liquid binder can be applied through one surface. Alternatively, if the spiral crimped and non-spiral crimped layers comprise a nonwoven web, the low melt binder fibers or binder particles may be combined with the non-spiral crimped layers and / or spiral crimps. The multilayer composite can be bonded using a smooth thermal calender roller that can be dispersed in the conductive layer. Preferably, the binder particles or fibers have a dimension of between about 0.2 mm and about 2 mm in at least one direction and between about 20 bonds / in 2 and 200 bonds / in 2 (3.1). (Bond / cm ² to 31 bonds / cm ² ) is added to the web. Low melting binder particles typically reach 5-25% of the product weight. When using binder fibers or binder particles, the binder melting temperature, the thickness of the other layers, and the activation temperature of the spiral crimp fiber can be used to avoid premature crimp activation during the bonding process. Preferably selected. That is, the temperature used during the bonding process is preferably not so high as to cause any substantial degree of spiral crimp to develop in the fibers of the spiral crimp layer.

  Other methods of intermittent bonding that can bond the layers together prior to heat treatment include chemical bonding and mechanical needling. By synchronizing with the web motion, a discontinuous needling pattern can be achieved using a needle plate that allows several needles to be on the same point. Alternatively, the adhesive can be applied intermittently in a pattern on the inner surface of the layer before they contact each other.

The bonds are preferably spaced from about 25 to 225 bonds / in 2 (3.9 to 35 bonds / cm ² ) at about 5 to 15 per inch (2 to 6 per centimeter). The bond density is kept low enough to maximize the length of the spiral crimped fiber segments between bonds, but at the same time is high enough to provide a durable adhesive composite sheet. Bond points can be circular, square, rectangular, triangular or other geometric shapes, and the bond area% can vary between about 5% and 50% of the surface of the nonwoven. The distance between adjacent bonds can be adjusted to control the fabric stretch level and can be optimized to a specific desired stretch level. In general, the distance between adjacent bond points or line ends is preferably in the range of 0.10 to 0.60 cm, more preferably in the range of 0.2 to 0.4 cm.

  The bonded multilayer composite can be heat treated in a tandem manner immediately after bonding, or the bonded fabric can be rolled up and heat treated during subsequent steps (dyeing, finishing, etc.). In a preferred embodiment of the present invention, the bonded multilayer composite is formed from a fibrous layer and heated in a wet finish process using hot water or steam, such as during conventional dyeing or finishing.

  If the multi-layer composite sheet is very light or the surface is very functional, for example if the non-woven web that is substantially unbound comprises one outer layer, the combined multi-layer composite sheet Is preferably heat treated under conditions in which the composite nonwoven fabric is uniformly shrunk under "non-shrinking conditions". “Conditions without shrinkage” means that there is virtually no contact between the web and the surface that can limit the shrinkage of the multilayer composite sheet. That is, there is no substantial mechanical force acting on the multilayer composite sheet that impedes or slows the shrinkage process. Alternatively, any surface that contacts the surface of the multi-layer composite sheet during the heat treatment process is a multi-layer composite that shrinks continuously so as to minimize the frictional forces that otherwise interfere with the shrinkage of the spiral crimpable layer. Moving at substantially the same surface speed as that of the sheet. Such a shrink-free process provides maximum shrinkage and maximum final elongation of the spiral crimped layer without the need for a wet finish.

1 is a schematic diagram of a process suitable for forming a stretchable bonded bi-layer nonwoven fabric in accordance with the present invention. FIG. 1 is a schematic diagram of a process suitable for forming a stretchable bonded three-layer nonwoven according to the present invention. FIG. FIG. 3 is a schematic cross-sectional view of an extensible bonded composite nonwoven fabric manufactured according to the process shown in FIG. 2. FIG. 3 is a schematic diagram of a side view of an apparatus suitable for performing a crimp activation process for free-falling a combined multilayer composite sheet from a first conveyor onto a second conveyor. FIG. 4 is a schematic diagram of a side view of a second apparatus suitable for performing a crimp activation process in which a combined multilayer composite sheet is suspended on a gas layer in a moving region between two conveyor belts. FIG. 5 is a schematic diagram of a side view of a third apparatus suitable for performing a crimp activation process in which a multilayered composite sheet bonded to a continuous driven rotating roll is supported during a heating process. FIG. 6 is a schematic diagram of a side view of a fourth apparatus suitable for performing a crimp activation step of a bonded multilayer composite sheet.

  FIG. 1 is a schematic diagram of a continuous process suitable for forming stretchable bonded bi-layer composite nonwoven fabrics in accordance with the present invention. A spiral crimpable nonwoven layer 3 is fed from a web source 1 such as a carding machine, feed roll, etc. and placed on a conveyor belt 5. A non-spiral crimpable layer 4 is fed from the second web source 2 and placed on top of the spiral-crimpable layer 3. To form a bonded two-layer composite fabric 7, the layered webs are bonded at the nip of a pattern bonder 6, such as a hot spot bonder. In order to heat the composite fabric to a temperature sufficient to activate the spiral crimp of the fibers of the spiral crimpable layer 3, the composite fabric 7 is passed through a heating position 8 to cause shrinkage, thereby causing non-spiral. The crimped layer 4 is buckled between bonding points to form pleats. Next, the heat-shrinked composite fabric 9 is wound up on the winding roll 10 as a finished product. Alternatively, roll up the web without heating in a wet finishing process, as is conventionally done with other hot water or steam shrink, dyeing, framing, and other “gray” fabrics such as finishing processes, It can then be heated and shrunk.

  FIG. 2 is a schematic diagram of a continuous process suitable for forming stretchable bonded multilayer composite nonwoven fabrics according to the present invention, wherein the spiral crimped nonwoven layer is two non-spiral shapes. It is sandwiched between crimped nonwoven layers. Non-spiral crimpable web layers 42 and 48 are supplied from web sources 41 and 47, respectively. A spiral crimpable multicomponent web 46 supplied from a web source 45 is placed between the non-spiral crimp layers 42 and 48. Optionally, pre-integrate the non-spiral crimpable layers by passing each layer through a nip formed by a pair of rolls 43 and 49 to form pre-integrated non-spiral crimp layers 44 and 50. can do. Pre-integration flattens the non-spiral crimped webs that allow their easier buckling between the bond points when the bonded three-layer composite is heat treated. A three layer assembly 52 is collected on the belt 51 and passed through a hot spot bonder 58 to form a three layer bonded composite 54. This is then passed to the heating position 55. The combined composite is heated to a temperature sufficient to activate the spiral crimps of the fibers of the spiral crimp layer 46, causing the spiral crimp layer to shrink and the non-spiral crimp layer Is buckled between the bond points to form pleats. Next, the heat-treated shrinkable composite fabric 56 is wound up as a finished product on a winding roll 59. Alternatively, the bonded, unshrinked multilayer composite nonwoven sheet 54 can be rolled up without heat treatment to activate spiral crimping in fibers comprising a spiral crimping layer, such as standard dyeing and finishing. Wet finishing can be done by using a process to do so.

FIG. 3 is a schematic cross-sectional view of an extensible bonded composite nonwoven fabric produced according to the process shown in FIG. The spiral crimped fiber in the spiral crimped layer has a bond point of 5
A substantially straight spiral coil segment 53 is formed in the plane of the spiral crimp layer between 7. The outer non-spiral crimpable fibers buckle to form a buckled segment 51. When the composite nonwoven fabric is stretched, the spiral crimped fiber segment 53 in the spiral crimp layer is stretched by drawing the spiral crimp, and the spiral crimped fiber segment is substantially completely straight. The buckling segment 51 of the second layer substantially stretches between the joining points 57. The spiral crimped fiber portion 53 acts as a spring and stretches when an extension force is applied to the fabric and has a recoil action whenever the extension force is released. The composite sheet structure of the present invention preferably has a recoverable elastic stretch of at least 12% in at least one direction forming a fabric having a natural dripping tendency. More preferably, they stretch at least 20% in at least one direction (ie, have a residual stretch or a permanent set of 5% or less) with substantially complete recovery.

  In order to obtain a very stretchable and strong fabric, the spiral crimpable fiber segment between adjacent bonds is long enough to provide the desired degree of stretch and is caused by a short connection between the bonds. Choose a sufficiently large spacing between couplings so that the impedance to stretching is minimized. As shown in FIG. 3, the non-spiral crimpable layer reinforces the final product without interfering with stretch recovery because the outer layer fibers are buckled “out of plane”. When a bias force is applied to the composite sheet, the spiral crimp fiber begins to stretch by extending the spiral crimp, which forms a linear layer (before shrinkage) as the bias force increases. Up to the limit of the original dimensions of the composite sheet, the folds are easily stretched and are not disturbed by the non-spiral crimp layer. When the bias force is released, the spiral crimp fibers recover their spiral crimp with a residual sheet stretch of preferably 10% or less based on the original sheet dimensions.

  FIG. 4 shows a schematic diagram of a side view of an apparatus suitable for performing a heat shrinking step under “shrink-free” conditions in one embodiment of the process of the present invention. An intermittently bonded multilayer composite sheet 60 comprising a spiral crimpable layer containing multicomponent fibers bonded to a non-spiral crimpable layer is moving at a second surface velocity. The composite sheet is transported on the first belt 11 moving at the first surface speed to the moving area A where the composite sheet is freely dropped until it contacts the surface of the second belt 12. The second surface speed of the second belt is lower than the first surface speed of the first belt. When the composite sheet leaves the surface of the belt 11, it is exposed to heat from the heater 13 while freely falling through the moving area. The heater 13 may be a blower to provide preheated air, an infrared heat source, or other heat source such as a microwave heater known in the art. While substantially free of any external interference forces, the composite sheet is heated in the transfer zone A to a temperature sufficiently high to activate spiral crimp and cause the composite sheet to contract. The temperature of the composite sheet in the moving region and the distance that the composite sheet freely falls in the moving region before contacting the belt 12 is such that the desired shrinkage is essentially reduced by the time the heat treated composite sheet contacts the belt 12. Selected to be complete. When the composite sheet first leaves the belt 11, it moves near the surface speed of the belt 11. As a result of the shrinkage resulting from the activation of the spiral crimp of the multicomponent fiber by heat applied in the moving zone, the surface velocity of the multilayer composite sheet decreases as it moves through the moving zone A. The surface speed of the belt 12 is selected to match as close as possible to the speed of the multilayer composite sheet when it leaves the moving area A and contacts the belt 12. Also, after shrinking, heating the surface portion of the fiber, or the low melting binder fiber blended with the main fiber, to a temperature that melts, activating the surface of the fiber using chemical means, or The composite sheet can be overbonded by impregnating the composite sheet with a suitable flexible liquid binder.

FIG. 5 shows an apparatus for use in the heat shrink process of the second embodiment of the present invention. The intermittently bonded multi-layer composite 20 comprises a layer of spirally crimped fibers intermittently bonded to a non-spiral crimpable layer, suspended on gas, and then second. Is transported on the first belt 21 moving at the first surface speed to the moving area A which is transferred to the second belt 22 moving at the surface speed. The second surface velocity is lower than the first surface velocity. A gas, such as air, is provided through an opening in the upper surface of the supply box 25 to float the combined multilayer composite as it is transported through the moving region. The air provided to float the composite is at room temperature (about 25 ° C.) or preheated to contribute to the shrinkage of the spiral crimped layer. Preferably, the air emanates from the small density and spaced openings in the upper surface of the air supply box to avoid interfering with the multilayer composite. The multi-layer composite can also be suspended in the air flow generated by small wings attached to rollers placed under the web. The radiant heater 23 (or other suitable heat source) activates the spiral crimp of the multicomponent fiber of the spiral crimp layer and moves the region to a temperature sufficient to cause shrinkage of the spiral crimp layer. In A, the suspended multilayer composite sheet is heated. The temperature of the multilayer composite sheet in the travel region and the distance that the multilayer composite sheet travels in the travel region is selected such that the desired shrinkage is essentially complete before contacting the second belt 22. The surface speed of the second belt is selected to match as close as possible to the speed of the heat treated multilayer composite sheet as it exits the moving zone A.

  FIG. 6 shows an apparatus used for the heat shrinking process of the third embodiment of the present invention. The multi-layer composite 30 comprises a spiral crimped fiber layer pattern bonded to a non-spiral crimp layer, from a continuous follower roll 34A to a belt 32 moving at a second surface speed. It is transported on the first belt 31 that is moving at the first surface speed to the moving area A that is transported on 34F. The second surface speed of the belt 32 is lower than the first surface speed of the belt 31. Although six rolls are shown in the figure, at least two rolls are required. However, depending on the operating conditions and the particular polymer used in the multicomponent fiber, the number of rolls can be varied. Multi-layer composite in moving zone A to a temperature sufficient to activate spiral crimping of the multicomponent fiber and cause shrinkage of the spiral crimpable fiber layer by radiant heater 33 (or other suitable heat source) Heat. The temperature of the multilayer fabric in the travel region and the distance that the fabric travels in the travel region is selected such that the desired shrinkage is essentially complete before contacting the second belt 32. As the spiral crimpable fiber layer contracts, the surface speed of the composite sheet decreases as it is conveyed through the moving region. Rolls 34A-34F are operated at progressively slower peripheral linear velocities in the direction of movement from belt 31 to belt 32, and the peripheral linear speed of each roll is the speed of the multilayer composite sheet when it contacts the roll. The surface speed of the individual rolls is selected to be 2-3%. The rate at which the spirally crimped layer shrinks is generally unknown and depends on the web structure, polymer used, process conditions, etc., thus maximizing composite shrinkage of the final product and minimizing non-uniformity By adjusting the speed of each roll during the process to enable the individual rolls 34A through 34F can be determined. The surface speed of the second belt 32 is selected to match as close as possible to the speed of the heat treated multilayer composite as it exits the travel zone A and contacts the belt 32.

FIG. 7 is a schematic diagram of a process for forming a two-layer composite nonwoven fabric according to the present invention, but using a simpler embodiment in a heat shrink process. The spiral crimpable nonwoven layer 103 is supplied from a web source 101 such as a carding machine, a supply roll, etc. and placed on a conveyor belt 105. The non-spiral crimpable layer 104 is supplied from the second web source 102 and is placed on top of the spiral crimpable layer 103. The laminar web is passed through the nip of the heat bonding rolls 106 and 107. Roll 106 is shown as a patterned roll, roll 107 is a smooth roll, and both rolls are heated to about 200 ° C. The belt 105 moves at substantially the same surface speed as the rolls 106 and 107 but at a sufficiently high speed so that activation of the spiral crimp layer is delayed immediately after the bonding is complete. Thus, separate heating locations 8 and 55 as depicted in FIGS. 1 and 2 are not necessary, respectively. In this embodiment, it is preferred that the non-spiral crimpable web supplied from the source is substantially unbonded, which aids the shrinking process as the composite exits the bond roll. After exiting the rolls 106 and 107, the heat treated and shrunk composite fabric 108 is then wound up as a finished product on the roll 109. This embodiment is not limited to a composite bilayer as depicted in FIG. For example, as depicted in FIG. 2, it is equally applicable to multilayer composites.

  The heating time for the crimp activation step is preferably less than about 10 seconds and typically less than 1 second. Longer heating generally requires expensive equipment. The web is preferably heated for a time sufficient to cause shrinkage of the multi-layer composite by at least about 10% in area because the spiral crimpable fibers develop at least 90% of their full spiral crimp. The The temperature for activating the spiral crimp should not be higher than about 20 ° C. below the onset of the polymer melt transition temperature, as determined by differential scanning calorimetry. This avoids undesirable early interfiber bonding. A number of heat sources including microwave radiation, preheated air, steam and radiant heaters can be used to heat the multilayer composite to activate crimping of the spiral crimped layer of fibers. After crimping is activated, the multilayer composite is preferably between about 10 and 75% in area, preferably at least compared to the area of the bonded multilayer composite before heat treatment. Shrink by only 20%, more preferably by at least 40%.

  Bonded multicomponent nonwoven fabrics made using the process of the present invention are strong, draped, elastically extensible, and have greater strength than multicomponent nonwoven fabrics made from single layer nonwoven webs.

Test Method Crimp Level Measurement The crimp properties for the multicomponent fibers used in the examples were determined by the method disclosed in Evans. This method comprises performing four length measurements of a wrapped bundle of multicomponent fibers in filament form (this bundle is called skein). These four length measurements are then used to calculate the four parameters to fully explain the crimp behavior of the multicomponent fiber.

The analysis procedure consists of the following steps.
1. ) A 1500 denier skein is produced from a multicomponent fiber package. Since the skein is a circular bundle, the total denier is 3000 when analyzed as a loop.
2. ) Skein on one end and apply 300gm weight on the other. Move the skein by gently moving it up and down four times and measure the initial length (Lo) of the skein.
3. ) Replace 300 gm weight with 4.5 gm weight and immerse the skein in hot water for 15 minutes. 4). ) The 4.5 gm weight is then removed and the skein is air dried. Again, skein and replace the 4.5 gm weight. After four runs, the skein length is again measured as the quantity Lc. 5. ) Repeat 4 times, replacing 4.5 gm weight with 300 gm weight. The length of the skein is measured as the quantity Le.

From the quantities Lo, Lc and Le, the following properties are calculated:
CD = crimp expression = 100 ^* (Le-Lc) / Le
SS = skewing contraction = 100 ^* (Lo-Le) / Lo
CI = crimp index, calculated similarly to CD, except that step 3 in the above procedure is omitted.

Volume Determination The volume of the nonwoven web is determined by multiplying the web thickness by the web surface area and dividing the resulting product by the weight of the web. Web thickness is measured with a spring loaded gauge using an applied force of 1 g / cm ² . The web surface area is calculated by multiplying the web length by the web width.

Elastic Elongation Determination The elastic elongation of the composite sheet was measured in the examples using a strip 2 inches (5 cm) wide by 6 inches (15 cm) long. With two marks located 2.5 cm from each end, 10 cm is measured along a length of 15 cm. The sample is first stretched 5% (eg, a length of 10 cm is stretched to 10.5 cm) and released. 30 seconds is allowed for sample recovery. This procedure is then repeated at 10%, 15%, 20%, etc. on the same sample to determine the highest level of elastic extension obtained for the sample.

Intrinsic Viscosity Determination According to an automated method based on ASTM D 5225-92, Viscotech Forced Flow for dissolved polyester at 19 ° C. with 50/50 wt% trifluoroacetic acid / methylene chloride at a concentration of 0.4 grams / dL. Intrinsic viscosity (IV) was determined using the viscosity measured with a Viscotek Force Flow Viscometer Y900 (Viscotek Corporation, Houston, TX).

Production of 2GT / 3GT bicomponent staple fibers Through a circular 68-hole spinneret with a spin block temperature of 255 ° C. to 265 ° C., polyethylene terephthalate (2GT) having an intrinsic viscosity of 0.52 dl / g, and 1.00 dl / g Parallel bicomponent filament yarns were produced by conventional melt spinning with polytrimethylene terephthalate (3GT) having an intrinsic viscosity. The polymer volume ratio in the fiber was controlled to 40/60 2GT / 3GT by adjusting the amount of polymer raw material during melt spinning. The filament was drawn from the spinneret at 450-550 m / min and quenched through conventional crossflow air. The quenched filament bundle was then drawn to 4.4 times its span length to form a continuous filament yarn having a denier per filament of 2.2. This was annealed at 170 ° C. and wound up at 2100-2400 m / min. For conversion to staple fibers, several wound packages of yarn are collected into a tow and fed into a conventional staple tow cutter, with a 1.5 inch (3.8 cm) cut length, and Staple fibers having a starting spiral crimp represented by less than 45% Cl were obtained.

Example 1
40% by volume poly (ethylene terephthalate) and 60% by volume poly (trimethylene terephthalate) were prepared as described above from card webs having a basis weight unit of 0.6 oz / yd ² (20.3 g / m ² ). ) And poly (ethylene terephthalate) / poly (trimethylene terephthalate) parallel bicomponent staple fibers. The two layers of this web were combined to form a spiral crimp layer. Each has a basis weight unit of 0.6 oz / yd ² (20.3 g / m ² ) and is composed of 1.5 inch (3.8 cm), 1.5 denier 2GT staple T-54 DuPont polyester. A spiral crimped layer was sandwiched between two card webs, one with MD orientation and the second with XD orientation. Using a flat steel roll heated to 210 ° C. and a diamond patterned steel roll heated to 205 ° C., and a calendar speed of 20 yards / min (18.3 m / min), a composite three-layer nonwoven fabric Was combined with a calendar bonder. With a 20% bonded area, approximately 0.70 inches (1.78 cm) center-to-center bond distance, the diamond pattern produced 225 bonds / in ² (35 bonds / cm ² ). The combined product weighed 3.0 oz / yd ² (102 g / m ² ). It had no stretch in the machine direction and about 15% elastic stretch in the cross direction.

A sample of the bonded multilayer nonwoven composite was placed in an oven for 3 minutes and heated to a temperature of 100 ° C. As a result of the heat treatment process, the sample contracted by about 10% in the machine direction and about 10% in the transverse direction. The heat treated sample had a basis weight unit of 3.6 oz / yd ² (122 g / m ² ) and 10% MD and 25% XD elastic elongation. The composite fabric was strong and durable and easily withstood 50 washing cycles.

Comparative Example A
Each of the outer layers is replaced by a layer of 0.6 oz / yd ² (20.3 g / m ² ) bicomponent 2GT / 3GT card staple web as described in Example 1 so that the multilayer composite fabric is the respective layer. A multilayer composite nonwoven fabric was prepared as described in Example 1 above, except that it consisted of four layers of bicomponent spiral crimped staple fibers of alternating MD and XD. Using the method described in Example 1, the layers were bonded and then heat treated. The bonded composite shrunk about 15% in the machine direction and about 25% in the transverse direction and had a post-heating elastic extension of 15% MD and 30% XD. The strength of the product was very low in both MD and XD, and the product had very low tear and abrasion resistance. The product had a rough and worn surface showing significant “pilling” and surface defects after only a few wash-dry cycles.

Example 2
The filament yarn described in Example 1 was placed by hand in a random manner to form a web weighing about 3 oz / yd ² (101.7 g / m ² ). A web was placed between two Spunbond Style 2250 Reemay® polyesters manufactured by BBA Corp. of Old Hickory, TN, Tennessee. Each fully bonded spunbond layer weighed 0.5 oz / yd ² (17.0 g / m ² ). Through a thermal pattern bonder with a patterned roll heated to 220 ° C. and a flat steel roll heated to 210 ° C., with a load of 150 lbs (263 N / cm) per linear inch, 20 yd / min (18.3 m / min) ) To process the composite. The pattern of bonding was spaced 8 / inch (3.1 / cm) with a 3.2 mm spacing between bonding and 29% bonding area%. After conjugation, the product was substantially nonextensible. The product was heat treated for 1 minute in a 150 ° C. air circulating oven and allowed to relax. It contracted about 10% in both directions. After shrinkage, the product weighed 4.6 oz / yd ² (156 g / m ² ) and had 15% longitudinal and 25% transverse elastic elongation. The outer Reemay® spunbond layer buckled when the product relaxed and was flat when the product was stretched in both directions.

Comparative Example B
Without the benefit of the outer layer, the bicomponent 2GT / 3GT filament web of Example 2 was subjected to the same bonding treatment as Example 2. Upon exiting the bonder, the product shrunk from 3 oz / yd ² (101 g / m ² ) to about 5.0 oz / yd ² (169.5 g / m ² ). It was poorly bonded and had a rough surface. When subjected to heat treatment at 150 ° C., it did not shrink further. Because binding failed in each direction with less than 10% extension, when MD or XD was extended, it had minimal extension and essentially no recovery.

Example 3
The filament yarn described in Example 1 was laid by hand in a random fashion to form a web weighing about 2.5 oz / yd ² (84.8 g / m ² ). A web was placed between two Spunbond Style 2253C Reemay® polyesters manufactured by BBA Corp. of Old Hickory, TN, Tennessee. Each lightly integrated spunbond layer weighed 0.5 oz / yd ² (17.0 g / m ² ). Both heated to 215 ° C. and combined through a heat bonder with patterned rolls and flat steel rolls at 30 yd / min (27.4 meters / min) at a load of 500 lbs per linear inch (877 N / cm) The thing was processed. The patterned roll had 20% bonded area percent, 333 pts / sq inch, and 0.025 inch square bond points on the sides of the diamond pattern. Under these conditions of binding points, shrinkage of the composite sheet occurred as the fabric exited the bond roll, as depicted in FIG. The product had a weight of 4.6 oz / yd ² (156 g / m ² ) and had a 21% longitudinal and 17% transverse elastic extension.

  Preferred embodiments of the present invention are as follows.

1. The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament A first polymer layer comprising at least 20% by weight of spirally crimped multicomponent fibers comprising a first polymer component and a second polymer component
A second polymer layer comprising less than 20 wt% laterally eccentric spiral crimped multicomponent fibers and intermittently bonded to the first layer;
A stretchable multilayer composite sheet comprising:
The spiral crimped multicomponent fibers in the first layer form a spiral crimped fiber segment located substantially in the plane of the first layer and connect the bonds; and A multilayer composite sheet in which two layers form a buckled out-of-plane segment between the bonds.

  2. The second layer is intermittently bonded to the first layer by a method selected from the group consisting of hot spot bonding, ultrasonic point bonding, mechanical needling, hydraulic needling, chemical bonding and adhesive bonding. 2. The multilayer composite sheet according to 1 above.

  3. The multilayer composite sheet of claim 1, wherein the composite sheet has a thickness of less than about 4 mm.

  4). The multilayer composite sheet of claim 1, wherein the composite sheet has a volume of less than about 30 cc / g.

  5. The first polymer layer comprises at least 50 wt% spiral crimped multicomponent fibers and the second polymer layer comprises less than 10 wt% spiral crimped multicomponent fibers. 2. The multilayer composite sheet as described in 1 above.

  6). The first polymer layer comprises at least 70 wt% spiral crimped multicomponent fibers and the second polymer layer comprises 0 wt% spiral crimped multicomponent fibers. 5. The multilayer composite sheet according to 5.

  7). The multilayer composite sheet of claim 6, wherein the first polymer layer consists essentially of spirally crimped multicomponent fibers.

  8). The multilayer composite sheet according to 1 above, wherein the first polymer layer is a nonwoven web selected from the group consisting of a card web, a cross-laid web, an airlaid web, and a multicomponent spunbond web.

  9. 2. The multilayer composite sheet according to 1 above, wherein the first polymer layer comprises warp yarns of multicomponent filaments.

  10. The multilayer composite sheet according to 1 above, wherein the second polymer layer is selected from the group consisting of a nonwoven web, a film, a knitted fabric, and a woven fabric.

11. ^{3. The} bond of claim ² , wherein the bonds are spaced between about 5 and 10 per centimeter at about 25 to 100 bonds / cm ² as measured when the multilayer composite sheet is substantially in tension. Multilayer composite sheet.

  12 The first polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is stretched not exceeding 90% of the length of the fully stretched chemical repeat unit structure. The second polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is a fully extended chemical repeat unit from the first polymer. 2. The multilayer composite sheet according to 1 above, having a structure approximate to the length of the structure.

  13. The unstretched first polymer component is poly (trimethylene terephthalate), poly (tetramethylene terephthalate), poly (propylene dinaphthalate), poly (propylene dibenzoate), copolymers thereof with ethylene sodium sulfoisophthalate And the stretched second polymer component is selected from the group consisting of poly (ethylene terephthalate), poly (cyclohexyl 1,4-dimethylene terephthalate), copolymers thereof, and ethylene terephthalate and ethylene. 13. The multilayer composite sheet as described in 12 above, which is selected from the group consisting of copolymers with sodium salt of sulfoisophthalate.

  14 14. The multilayer composite sheet according to 13, wherein the first polymer component and the second polymer component are arranged in a parallel structure.

  15. The multilayer composite sheet of claim 1, wherein the composite sheet has a recoverable elastic elongation of at least 12% in at least one direction.

16. The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament Providing a spirally crimpable polymer layer comprising at least 20% by weight of spirally crimpable multicomponent fibers comprising a first polymer component and a second polymer component;
Providing a non-spiral crimped polymer layer comprising less than about 20% by weight of side eccentric spiral crimped multicomponent fibers;
Intermittently bonding the first polymer layer to the second polymer layer by a plurality of bonds to form a bonded multilayer composite sheet;
Heating the bonded multi-layer composite sheet to a temperature sufficient to develop a three-dimensional spiral crimp in the spiral crimpable fibers in the first layer, wherein the area is at least an area based on the original sheet area; Shrinking the bonded multilayer composite sheet by 10% and buckling the second polymer layer between the bonds;
A process for producing an extensible multilayer composite sheet comprising:

  17. 17. The method of claim 16, wherein during the heating step, the bonded multilayer composite sheet shrinks by at least 20% by area based on the original sheet area.

  18. The spiral crimpable layer comprises at least 50% by weight of spirally crimpable multicomponent fibers, and the non-spiral crimpable layer comprises less than 10% by weight of spirally crimpable multicomponent. 18. A method according to 17 above, comprising a fiber.

  19. The spiral crimpable layer comprises at least 70% by weight of spirally crimpable multicomponent fibers, and the non-spiral crimpable layer is approximately 0% by weight of spirally crimpable multicomponent. 19. A method according to claim 18 comprising a fiber.

  20. 17. The method of claim 16, wherein the spiral crimped layer is selected from the group consisting of warp yarns of multicomponent filaments and multicomponent nonwoven webs.

  21. 17. The method of claim 16, wherein the non-spiral crimpable layer is selected from the group consisting of a film, a nonwoven web, a knitted fabric and a woven fabric.

  22. 21. The method of claim 20, wherein the spiral crimped layer is a nonwoven web selected from the group consisting of a multicomponent card web, a multicomponent crosslaid web, a multicomponent airlaid web, and a multicomponent spunbond web. .

  23. The method of claim 21, wherein the non-spiral crimped layer is a nonwoven web selected from the group consisting of a card web, a multi-component cross-laid web, an air-laid web, and a spunbond web.

  24. The method of claim 16 further comprising the step of pre-integrating the non-spiral crimpable layer prior to bonding to the spiral crimpable layer.

  25. 25. The method of claim 24, wherein the non-spiral crimpable layer is pre-integrated by mechanically planarizing the layer.

  26. The method of claim 25, wherein the non-spiral crimpable layer is planarized by passing the layer between nips formed by two rotating rolls.

  27. The above intermittent bond is formed by using a bonding method selected from the group consisting of hot spot bonding, ultrasonic point bonding, mechanical needling, hydraulic needling, chemical bonding, and adhesive bonding. The method described.

28. 28. The method of claim 27, wherein the bonds are spaced between about 3.9 and 31 bonds / cm ² and between about 2 and 8 per centimeter.

  29. 17. The method according to 16 above, wherein the heating step is performed under conditions without shrinkage.

  30. The method of claim 16, wherein the heating step comprises a wet finishing process.

  31. 31. The method of claim 30, wherein the wet finishing process is a dyeing process.

  32. The first polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is stretched not exceeding 90% of the length of the fully stretched chemical repeat unit structure. The second polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is a fully extended chemical repeat unit from the first polymer. 17. The method according to 16 above, wherein the structure approximates the length of the structure.

  33. The unstretched first polymer component is poly (trimethylene terephthalate), poly (tetramethylene terephthalate), poly (propylene dinaphthalate), poly (propylene dibenzoate), copolymers thereof with ethylene sodium sulfoisophthalate And the stretched second polymer component is selected from the group consisting of poly (ethylene terephthalate), poly (cyclohexyl 1,4-dimethylene terephthalate), copolymers thereof, and ethylene terephthalate and ethylene. 33. The process of claim 32, selected from the group consisting of copolymers with sodium salt of sulfoisophthalate.

  34. 34. The method according to 33, wherein the first polymer component and the second polymer component of the multilayer composite sheet are arranged in a parallel structure.

  35. The method according to 16 above, wherein the intermittent joining step and the heating step are performed substantially simultaneously.

36. The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament A first polymer layer comprising at least 20% by weight of a spiral crimped multicomponent fiber comprising a first polymer component and a second polymer component
A second polymer layer comprising less than 20 wt% laterally eccentric spiral crimped multicomponent fibers and intermittently bonded to the first layer;
Further comprising
The spiral crimped multicomponent fibers in the first layer form a spiral crimped fiber segment located substantially in the plane of the first layer and connect the bonds; and Two layers form a buckled out-of-plane segment between the bonds,
A fabric article comprising a stretchable multilayer composite sheet.

Claims (3)

The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament Comprising at least 20% by weight of a spiral crimped multicomponent fiber comprising a first polymer component and a second polymer component, wherein the first polymer component and the second polymer component are in parallel Arranged in a structure, wherein the first polymer component is a partially crystalline polyester, wherein the chemical repeat unit of the crystalline region is 90 times the length of the structure of the fully extended chemical repeat unit. % In a non-elongated stable structure and the second polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is from the first polymer. , In the structure of approximating the length of the fully extended structure of chemical repeat units, and the first polymer layer,
A second polymer layer comprising less than 20 wt% laterally eccentric spiral crimped multicomponent fibers and intermittently bonded to the first layer;
A multilayer composite sheet for stretchable apparel comprising
The spiral crimped multicomponent fibers in the first layer form a spiral crimped fiber segment located substantially in the plane of the first layer and connect the bonds; and Two layers form a buckled out-of-plane segment between the bonds, where the bond is between 3.9 and 35 bonds / cm ² when the multilayer composite sheet is substantially unstretched. With a spacing of 2 to 6 per cm,
A multilayer composite sheet for stretchable clothing characterized by the above. The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament Comprising at least 20% by weight of a spirally crimped multicomponent fiber comprising a first polymer component and a second polymer component, wherein the first polymer component and the second polymer component are Arranged in a parallel structure, wherein the first polymer component is a partially crystalline polyester, wherein the chemical repeat unit of the crystalline region is the length of the structure of the fully extended chemical repeat unit In an unstretched stable structure that does not exceed 90% and the second polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is the first polymer Ri, in the structure of approximating the length of the fully extended structure of chemical repeat units, providing a spirally-crimpable polymeric layer,
Providing a non-spiral crimpable polymer layer comprising less than 20 wt% lateral eccentric spiral crimpable multicomponent fibers;
Intermittently bonding the first polymer layer to the second polymer layer by a plurality of bonds to form a bonded multilayer composite sheet;
Heating the bonded multi-layer composite sheet to a temperature sufficient to develop a three-dimensional spiral crimp in the spiral crimpable fibers in the first layer, wherein the area is at least an area based on the original sheet area; Shrinking the bonded multilayer composite sheet by 10% and buckling the second polymer layer between the bonds;
Stretching wherein the bonds are spaced from 2 to 6 per cm at 3.9 to 35 bonds / cm ² when the multi-layer composite sheet is substantially unstretched comprising A possible method for producing a multilayer composite sheet for clothing. The multicomponent fibers have a cross section and a length and are arranged in substantially different laterally eccentric regions across the cross section of the multicomponent filament and extend substantially continuously along the length of the multicomponent filament Comprising at least 20% by weight of a spiral crimped multicomponent fiber comprising a first polymer component and a second polymer component, wherein the first polymer component and the second polymer component are in parallel Arranged in a structure, wherein the first polymer component is a partially crystalline polyester, wherein the chemical repeat unit of the crystalline region is 90 times the length of the structure of the fully extended chemical repeat unit. % In a non-elongated stable structure and the second polymer component is a partially crystalline polyester, wherein the chemical repeat unit in the crystalline region is from the first polymer. A first polymer layer on the structure of the fully approximated to the length of the structure of the extended chemical repeat units,
A second polymer layer comprising less than 20 wt% laterally eccentric spiral crimped multicomponent fibers and intermittently bonded to the first layer;
Further comprising
The spiral crimped multicomponent fibers in the first layer form a spiral crimped fiber segment located substantially in the plane of the first layer and connect the bonds; and Two layers form buckled out-of-plane segments between the bonds,
Stretchable multilayer composite characterized in that the bonds are spaced from 2 to 6 per cm at 3.9 to 35 bonds / cm ² when the multilayer composite sheet is substantially unstretched A cloth article for clothing comprising a sheet.

Images